Renewable energy sources such as wind, solar photovoltaic (PV), or tidal are becoming an increasingly important source of electrical power generation. Many renewable energy sources produce Direct Current (DC) power which normally must be converted into Alternating Current (AC) power before it can be consumed. DC to AC conversion is performed by a device known as an inverter. Previously, an array of PV panels would connect to a single, large central inverter. Recently however, “microinverter” technology has been developed in which each PV panel is equipped with its own dedicated inverter and each PV panel and associated inverter outputs AC power. Microinverters offer potential advantages over central inverters including maximum power point tracking (MMPT) on a per PV panel basis, elimination of DC power busses, easy addition of incremental panels and more robust fault tolerance. Microinverters also offer the ability to monitor the performance of a PV array at the panel level affording detailed diagnostic data on a per panel basis.
Although microinverters have potential advantages, there are also potential problems associated with their use. In particular, since a single microinverter is associated with each PV panel in an installation, the cost of each individual microinverter should be kept as low as possible. Further, with the microinverters located at the PV panels, replacement or maintenance can be more difficult due to the location of PV panels, for example on a building's roof.
The lifetime cost of a microinverter can be lowered by reducing the initial cost of the inverter, for example by using less expensive components; by extending an expected lifetime of the inverter; by reducing maintenance required throughout the lifetime of the inverter; or by combinations thereof.